In the home and the workplace, there exists the potential for heat loss through gaps in the sealing of doors, windows and other openings in the building structure. Conventionally, attempts are made to minimize such heat loss by weather-stripping, caulking and otherwise sealing such gaps. In this regard, there exists a potential for heat loss through mail slots, typically situated in or alongside entrance doors. Such conventional attempts at sealing however, have little practical application to mail slots. For instance, while it appears practical to weather-strip mail slots about the outer peripheral edges of the mail slot underlying the outside mail slot door, such weather-stripping utilization simply exacerbates the problem in that it prevents the outside door from fully closing.
There has been at least one patent directed towards the need to insulate mail slots. U.S. Pat. No. 2,437,319 entitled AIR TIGHT MAIL SLOT, which issued to P. T. Gable et al on Mar. 19, 1948 provides an air tight mail slot insert incorporating doors on the inside and the outside of the mail slot. The construction of this insert includes an inwardly pivoting, elliptically shaped door covering the outside opening of the mail slot and a vertically sliding door located on the inside of the mail slot. The outside door is provided with a downwardly extending pin. When the outside door is pushed inwardly into an open position, the pin coacts with a flange attached to the inside door to simultaneously raise the inside door into an open position.
In this regard, designs for mail slots and building receptacles have incorporated inside doors for a variety of purposes. For instance, British Provisional Patent Specification entitled AN IMPROVEMENT IN OR RELATING TO THE PROVISION OF LETTER BOXES IN WOODEN DOORS, which issued to G. Platt et al on Oct. 1, 1981, provides a pair of inside and outside pivotable doors mounted on a casement type of insert. This casement is to be utilized within a rough hewn slot-like opening in a door to thereby save the time and the expense involved in finishing the opening. A more common purpose is for convenience of deposit and collection of oversized articles. U.S. Pat. No. 460,742 entitled HOUSE DOOR LETTER BOX, which issued to E. Markell on Oct. 6, 1891 provides an outwardly pivoting indoor mail slot door for the receipt of letter sized articles and an outdoor receptacle for oversize packages.
The teachings of such prior art inventions, as discussed above, are limited to the provision of inside doors on frames and casements which are in turn installed within newly constructed mail slots. They therefore, do not provide the consumer with an adequate and inexpensive means to seal conventional existing mail slots without completely rebuilding the existing mail slot and discarding the used mail slot hardware. This is because mail slots are not uniform in size; and thus the insert and casement structures disclosed by the prior art patents would not fit within different sized mail slots without modification to the mail slot by enlargement or reduction.
The present invention, therefore contemplates the provision of an indoor mail slot cover to be utilized without modification of the existing mail slot or mail slot hardware. However, because the building structure can limit the amount of space available for the installation and because mail slots are not uniform in size, the present invention encompasses means to reduce the size of the mail slot cover in accordance with such attendant space restrictions and with the size of the mail slot. Moreover, since the indoor mail slot cover can be utilized within the interior of the home, there are esthetic considerations which necessitate a neat and professional appearing installation. Such esthetic consideration often require reduction of the size of the mail slot cover in accordance with the size of the mail slot.